The public is becoming increasingly aware of damage to the skin caused by sunlight, and particularly the ultraviolet (UV) components of sunlight, such damage including various types of skin cancers and early “leathering” and aging of the skin. As a result of this knowledge, sunscreen lotions and creams, as well as cosmetics containing sunscreens, are now available and sold to the public in increasing varieties and amounts, and at various protection (SPF) levels.
Although also well known, but less well known than damage caused to uncovered skin by UV, sunlight also passes through clothing, more or less depending on the openness of the fabric from which the clothing is made and the material itself. For example, normal light weight cotton clothing, commonly worn in summer, is relatively poor in blocking UV rays. Cotton is not a strong UV absorber and UV light is only moderately attenuated when it passes through normal cotton clothing. There is accordingly a need for blocking UV rays that pass through normal cotton clothing, especially the lightweight type commonly used in summer time, e.g. T-shirts and the like, as well as clothing made from other fabrics as well, e.g. cotton-polyester blends, nylon, nylon blends, and also regenerated cellulose, flax, linen, etc., and blends thereof with one another or other fibers.
There are UV-blocking clothes on the market that permit air-flow while blocking UV, but these clothes tend to be expensive. Some relatively recent U.S. patents which relate to the industrial treatment of yarns, fibers, fabrics and finished textiles to enhance their UV absorption or attenuation include U.S. Pat. Nos. 5,637,348; 6,015,504; 6,610,214 and 6,641,920.
Because factory-UV-treated textiles are quite expensive, it would be desirable to provide means for treating clothing, especially lightweight summer clothing, in the home, i.e. domestically, and there are basically three ways to do this, namely: (1) incorporating the UV attenuation or blocking material in a laundry detergent composition, (2) providing such a material as a separate powder for use with a laundry detergent, or (3) in accordance with the present invention as described below.
Incorporation of the UV blocking material with laundry detergent is inconvenient because the household then needs to have two different kinds of laundry detergents, one including the blocking material and one not including the blocking material; or, alternatively, a single household detergent can be used containing the UV protectant material, but in that case the cost increases substantially because articles such as linens, underwear and bed clothing are also impregnated with UV protectant, which is unnecessary and wasteful.
The second option is one commercially available, noting for example the Rit® Sun Guard™ Laundry Treatment (see www.ritdye.com/sun_guard/faq.asp). The Rit® system, which includes Tinosorb™ FD, a UV protectant produced by CIBA Specialty Products as active ingredient, requires its use with laundry detergent, i.e. it is simply added as a powder to the regular wash load, preferably without the addition of chlorine bleach. While this system is an improvement over incorporating the UV protectant in the laundry detergent, it also is not convenient because separate doses must be pre-packaged for different wash loads, or there is always a measurement problem. In addition, opening the packet of the UV protectant powder and dumping the entire contents or a portion of the powder into the washing machine creates a danger from possible inhalation of some of the powder.